


Charmer

by kali_asleep



Category: Harry Potter - J. K. Rowling, Sherlock (TV)
Genre: 2nd chapter pwp, Crack, Eventual Smut, M/M, Magic, Nudity, PWP, Red Pants, Slow Burn, Smut, sherlock is a prick
Language: English
Status: Completed
Published: 2013-02-19
Updated: 2015-04-25
Packaged: 2017-11-29 20:56:54
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 8,725
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/691358
Author URL: https://archiveofourown.org/users/kali_asleep/pseuds/kali_asleep
Summary: <blockquote class="userstuff">
              <p>“A-and, well,” he faltered momentarily. “And, well, you’re definitely not well known for your charm. No offense, but with your general attitude, you certainly wouldn’t be charming the pants off of me!”</p><p>Sherlock tries to charm the pants off of John. It's met with mixed success.</p><p>Sherlock/Harry Potter AU Crossover</p><p>FINALLY COMPLETE, NOW WITH 100% MORE SMUT</p>
            </blockquote>





	1. In which Sherlock is charming, and trousers are not pants.

**Author's Note:**

  * For [QuinnAnderson](https://archiveofourown.org/users/QuinnAnderson/gifts).



> This started as an impulsive fill of my desire for Potterlock. As soon as I can figure out/remember how links work, I will post a proper link to the picture that inspired it all, but for the time being, check out this excellent piece of work by tumblr artist selleryattacks: http://selleryattack.tumblr.com/post/43378260838/potterlock
> 
> My actual fill, along with the picture can be found here: http://fuckyeahteenlock.tumblr.com/post/43489749473/fuckyeahteenlock-selleryattack-potterlock 
> 
> though that may be changing as I figure out how to make sure the credit for my work stays my own! While this was posted on the fuckyeahteenlock tumblr run by QuinnAnderson and myself, it'll also be posted on my personal tumblr.
> 
> Enjoy!

“John, wait up!”

 

At the sound of his name John stopped, drawing huffs of protest from the other students as they passed out of the classroom. Amidst the milling bodies the birch-brown head of one Molly Hooper bobbled forward, arms waving frantically in John’s direction. John stepped off to the side of the hall and waited with a small smile.

 

“Hullo, Molls. Sorry to leave you back there.”

 

Molly stopped in front of him and shot him a wide grin. “Oh, no worries, I just needed to ask Professor Flitwick a question about tonight’s theory homework.” Even as she spoke, a light flush rose to her cheeks, and she glanced away from him; John was no Seer, but he did know when his fellow Hufflepuff was being not-too-entirely-truthful.

 

“Uh-huuh,” he drawled, “And you weren’t at all trying to catch Sherlock’s attention, were you?”

 

The squeak burst from Molly’s mouth was even more noticeable than her intensifying blush. Several students turned to look at the two curiously, some even gesturing between Molly and John and nodding. While many outside of Hufflepuff regularly mistook the two friends for something more, anyone who knew Molly and had spoken with her for more than ten minutes knew where her affections lay: the infamous Sherlock Holmes.

 

“Oh, but did you see how he did the _Auguamenti_ on the very first try?” The girl’s voice pitched into a scandalous whisper. “He could draw water from me _any time_.”

 

John let loose a loud guffaw. “Molly!”

 

He began to walk, trying to ignore the tug of a blush about to rise on _his_ cheeks. Molly tittered and hopped to catch up, looking across to John with wide, mischievous eyes.

 

“I mean, his hands? His fingers? The way he works a wand ought to be illegal!” A small hand flew to Molly’s mouth as soon as the words were out, but she giggled through her fingers. “Well, I didn’t mean _that_ way, though…”

 

“Molly, I don’t even want to _think_ about where you’re going with that.” John shifted his books in his arms slightly, whole body mildly uncomfortable (and perhaps a little warm) as his mind raced to _exactly_ where Molly was going with it. Though John would never admit it, the entire school seemed to have mutually agreed that Sherlock Holmes was unusually attractive. The praise tended to end there, however: while _everyone_ knew of Sherlock’s startling adeptness with his studies, _everyone_ also knew of his terrible temper, abominable manners, and sheer rancor with which he tore other student’s personal lives wide open. Nonetheless, there were times when John would find himself fixated on the Ravenclaw’s lithe form as he practically danced around his silver cauldron, or captivated by the striking sapphire of his eyes as he worked through a particularly challenging charm. John shook his head. Molly again laughed (more knowingly than either would care to admit).

 

“All I’m saying is that, if he wanted to, he could charm the pants off of me like _that_.” She snapped, vivid fuchsia sparks lighting from her fingertips as she did.

 

Pushing a hand through his hair in embarrassment (and maybe some exasperation), John rolled his eyes.

 

“Sorry, but I don’t think Sherlock Holmes could _charm_ the pants off of anyone. You know what he’s like!”

 

Molly opened her mouth to respond, but suddenly bit off the retort.

 

“And how exactly is that?”

 

The deep voice crackled through John’s frame, reminding him simultaneously of lightning and bright veins of freezing water jutting through a stream. At the sound John tried to stop and turn; the jerky motion nearly sent him careening into the abominably high chest of one 6th year Ravenclaw. John caught himself in time and played off his near fall smoothly, but the quirked lips in Sherlock’s otherwise stoic face revealed his flub had been caught.

 

Molly practically hunkered behind John, face bright red. Sherlock stared down at them both, uncharacteristically patient. So that was that, then. John shifted his stance, planting his feet firmly and tilting his chin up. He had been caught, yes, but that didn’t mean he had to crumble under Sherlock’s scrutiny (as so many others did). No, he would be defiant.

 

“Well, you’re not exactly the friendliest bloke around here, are you?” John began. Around him, students had started to pause in the hall, whispering excitedly as they waited for Sherlock to eviscerate the rather unassuming John Watson. Sherlock continued to look down at him, expression unchanging.

 

“A-and, well,” he faltered momentarily. “And, well, you’re definitely not well known for your charm. No offense, but with your general attitude, you certainly wouldn’t be charming the pants off of _me_!” As soon as they were out of his mouth, John knew his words would be gossip fodder for weeks. Nonetheless he stood his ground, glaring up at the other boy. The crowd around them seemed to draw a collective breath, waiting for the inevitable and infamous insult.

 

Instead, a chuckle. Sherlock swooped down to peer at John eye-to-eye; too surprised to blink, John held fast. Eyes locked, and John was overwhelmed with the blue of a river rushing to meet the mouth of the sea.

 

“Curious…” Sherlock muttered, voice so low that only John could hear. “And are you willing to test that, Watson?”

 

The words seemed to trickle slowly into John’s shocked brain; by the time he was capable of responding, Sherlock had flounced off and the crowd’s curious whispers had swelled to a roar. Finally, John spoke.

 

“Oi!”

 

~

 

It took an entire week before John noticed anything unusual.

 

As a sixth year and a strong student he was fairly caught up in his preparations for his OWLS, and as such spent much of his spare time in the library, and much of his time in the halls distracted. As such, the angry exclamations over spells that whipped past his ears and nearly hit the students behind him went unheard; Filch’s increased angry postings of “NO SPELLS IN THE HALLWAYS” went unnoticed.

 

Not until Professor McGonagall made a rather harried announcement over the din of breakfast in the Great Hall did John truly notice something was amiss. Wand pressed lightly over her throat, she made the all-call that left teenagers tumbling through the rumor mill all day.

 

“As a reminder to students of _all_ ages, there is to be absolutely no practice of magic in the hallways between classes. Any students caught infracting on this time-honored rule will promptly be given a week’s detention.”

 

Halfway through a mouthful of eggs, John turned to another Hufflepuff at the table, Mike. “What’s that all about?”

 

Mike’s eyes widened, and he shook his head in disbelief. “You mean you haven’t noticed? There’ve been spells flying around all willy-nilly for weeks! How far is your nose up those books that you didn’t notice? It happened just yesterday when we were coming up from the dungeons after potions!”

 

John chuckled and shrugged, ready to go back to his food. Mike, however, continued.

 

“You know, folks are saying it’s some sixth year curse, as they’re always happening outside of our classes.”

 

“Hnnn,” John mumbled, already distracted from the gossip as he practiced the motions of a challenging Transfiguration spell with his fork. Mike continued to chatter while John worked, and it was only as John was looking up to respond to one of Mike’s half-heard questions that he met eyes with someone across the tables. Sherlock, hands folded under his chin, was gazing at him intently from the Ravenclaw table. Their eyes remained locked for seconds, blue-on-blue, before Sherlock abruptly stood up, abandoning his plate of uneaten food.

 

“Looks like Holmes has taken a fancy to you,” Mike said, smile evident in his voice.

 

“What?”

 

“He’s been lookin’ at you like that for days, mate.”

 

~

 

The very next day, John bent to re-tie his shoe at the exact moment that a spell surged along his back and hit the suit of armor behind him. The electric tingle of magic and the jarring clank of the armor’s head falling to the stone floor were the only things that clued John in to the spell’s presence, and at the sound he jolted up and spun around wildly. Overfilled with bodies as the hall was, John couldn’t make out who had sent to spell in his direction, though the startled looks from the students closest to him served to rule out some.

 

Cautiously, John made his way to Charms. There, he bumbled through the lesson on summoning, too occupied by the seemingly ever-present (and eerily unblinking) stare of the handsome Ravenclaw across the room. John scurried from the classroom as soon as they were dismissed, only to be forced to stop as a spell struck the bag tucked against his side and released all of his books and papers in a messy torrent.

 

He cursed under his breath. Molly rushed out to help him gather his things, a rather confused looking Flitwick following after to continue answering whatever question it was the Hufflepuff girl had prompted. Sauntering behind them both was Sherlock, bag slung low across his back, posture easy as he casually regarded the scene in front of him.

 

“Distracted, Watson?” he asked archly. Nonetheless, the Ravenclaw kneeled down next to John and Molly and started bundling the fanned pages of John’s Herbology notes. He passed them to a shocked looking John.

 

“Thank you.”

 

Sherlock glanced up, a flicker of surprise quickly masked by a more appraising look. “You’re unusual, Watson. You do know that?”

 

“Coming from you, I’ll take that as a compliment,” John said. He shoved the last of his books into the makeshift bag Molly had conjured from a (now very grumpy looking) bit of tapestry. Standing, he held a hand out to Sherlock. Sherlock hesitated; John grabbed the boy’s hand and yanked him up. For a moment, Sherlock looked as though he was about to say something, but then pivoted sharply on one heel and strode off in the other direction.

 

~

 

He still had not replaced his school bag, and the jokes he received from Mike and Greg (a Gryffindor, though they tried not to hold it against him) about the girlishness of his tapestry tote were endless the following day. Grumpily, John stayed planted firmly in his seat at the end of Defense Against the Dark Arts, ignoring their protests and coaxing to come to lunch. Finally they gave in and left, comments somewhere between heckling and chagrin. After a few minutes John got up and made his way to lunch. The halls were sparsely populated, with most students in the Great Hall for lunch or back in their dorm rooms for a break before their next class. A trio of forth year Slytherins slunk past him and turned the corner, muttering to each other.

 

“Crazy git…” one of them hissed. “Absolutely off his rocker,” another said. “I don’t care _how_ pureblooded his family might be, he’s a right wanker.”

 

John was hardly surprised to see Sherlock on the other end of the hall, coming his way. The boy’s dark curls, a shade too long, shook as he walked with distracted purpose. Softly colored light drifted through the castle’s stained glass windows and played along Sherlock’s face, tinting his skin and creating enchanting shadows along the lines of his cheekbones and jaw. John and Sherlock were drawing closer to one another. While Sherlock was gazing distantly at some point far down the hall, John’s eyes were totally fixated on the approaching figure. He _was_ beautiful. Captivating, even.

 

Without seeming to register his presence, Sherlock passed John.

 

The briefest breath of fabric against fabric, a dark, whispered word, and then a sudden wash of cold air.

 

There was no time for a reaction. John came to a dead stop in the hall, and slowly turned. He was nearly nude.

 

Sherlock continued ambling down the hall, though now he fixed John with a cocky side glance. His eyes swept from John’s crimson face down his chest to an equally crimson pair of pants. Suddenly lacking both robe and uniform, John stood exposed and thunderstruck. Somehow his scarf had remained un-spelled: the black and yellow scarf stood out like a flag, and his red pants seemed a bright warning. Sherlock stopped walking as his eyes raked up John’s frame, and for a moment the pants seemed to John to be less warning and more invitation. John’s pants were slightly too tight, a product of a mid-year growth spurt; the white trim at his waist and the thin, red cotton at the groin clung noticeably. John wriggled from foot to foot as he fruitlessly tried to cover himself with his bag, and Sherlock’s pale eyes narrowed, darkened to azure.

 

After what seemed like centuries, John parted his mouth to speak. Sherlock’s gaze darted from his pants back to his face, and a sly smirk flitted over his lips.

 

“Sher—“

 

“Holmes! Watson! Wh-wha?”

 

Professor McGonagall was stopped at the corner, leaning heavily on the wall with a shaking hand as her face turned an unhealthy beet purple. She looked between the two of them and shook her head vigorously. Both boys simultaneously moved to explain, though neither knew quite how.

 

“I don’t even care!” she yelled shrilly. The two boys did not look at each other, and McGonagall would not meet their repentant stares.

 

“Detention! Starting tonight! One. Whole. Week!”

And in a flurry of robes and agitated huffs, McGonagall stormed off. Without a sound, Sherlock took off down the hall, leaving John speechless, bag-less, and still entirely undressed.

 

~

 

 


	2. Chapter 2

**Summary for the Chapter:**

> In which I am particularly bad at Britishisms, or, The Impetus Behind this Entire Chapter

**Notes for the Chapter:**

> Thank you to everyone who so patiently and wonderfully continued to leave me kudos and comments long after most of you were bound to expect this had been abandoned. Yes, this did take over a year to complete. This is my first honest attempt at smut, and I really got hung up on that - I'm probably not just a smut writer... nonetheless, I hope that this is enjoyable and not terrible and that you forgive me for using British terms like pepper - unpredictably and just kind of shaken in everywhere.
> 
>  
> 
> A zillion thanks to my best friend and biggest fan, QuinnAnderson, whose work you absolutely need to read. She not only wrote an entire smut guide to help me through this, but gave me tons of encouragement and even offered to write the end for me. I hope I've done you proud-ish, Honey Bee.

Detention was one week, in the library, re-shelving a set of stacks in the Magical Creatures section, somewhere between _Thestral (Horse, Winged)_ and _Occamy_. Nearly eight in all, tucked in one of the Eastern corners (of which there were many) in section remote enough that John wasn’t entirely sure he’d ever ventured there.

Sherlock was already there when he arrived and was leaning against one of the stacks with an unrolled length of parchment in his hands. On a cart near his hip waited rows of books to be ordered; every few seconds another would appear on the cart with a faint whisper of pages. The boy had abandoned his robes but kept his vest; between pushed up shirt sleeves and an un-tucked hem, Sherlock was the very image of arranged disarray, a neatly ordered mess under a pair of piercing eyes. Sherlock stared John down as he approached, and thrust the parchment to him as soon as he was near enough. John took the paper but did nothing else, waiting. He expected nothing like an apology from the Ravenclaw boy, but he did at least anticipate an explanation for why exactly Sherlock had done what he did to put them both in detention. John had tried exceedingly hard not to think about what had happened the day before—he’d been spared an audience to his ignominy, and had managed to lie gracefully to those who even knew he’d got a detention—but now that he was face-to-face with the source of all his sudden woes, it was a struggle _not*_ to think on it. The sudden dark of Sherlock’s eyes. The flush rising up his neck. And, of course, John’s unexpected and utterly humiliating near-public-nudity.

Curiosity wrestled with rage as he stood.

“And?” John snapped.

The syllable held in the air, long enough for John to notice. Discomfort was pushing out curiosity even as rage spiked when Sherlock finally replied.

“And…?” he drawled.

“I think you owe some kind of apology, or, or reasoning for what _happened_ in the hallway!”

Even in profile Sherlock’s eye roll was impressive, if not entirely too dramatic given John’s seemingly reasonable demand. He did not turn from the book he was shelving, nor did he deign to make eye contact with John.

“ _Boring_. If you need some kind of explanation for my efforts, then perhaps you’re too dense to merit them in the first place,” Sherlock said, after which he remained silent for the rest of the evening.

…

The second night of detention, John went for a more tactful approach.

“Look, if I offended you with what I said outside of Charms that day, I’m sorry. I know you get enough grief from the other students; you don’t need it from me.”

That made Sherlock look up. His gaze was so intense that everything around him seemed to sharpen: line of nose, edge of cheekbone, spiral of hair all cut into John’s mind.

“I was hardly offended and you’re far from those imbeciles I’m forced to call _peers_.” The words came out in a flurry, and it took John a moment to comprehend Sherlock’s words. He was about to comment on how surprisingly not backhanded Sherlock’s compliment was, when suddenly the other boy added:

“Certainly, you lack the sort of base imagination necessary for creative cruelty.”

John sputtered, then blushed, wishing his responses to Sherlock’s snark weren’t so ham-handed. As his nails dug into his palms, John almost understood why students bullied Sherlock so: one word from the boy jerks like an ankle unexpectedly rolled, leaving the recipient pained, off-kilter, and vehemently embarrassed. Still, John caught himself and showed at least half a second of rational thought before responding.

"Did anyone ever tell you too many comments like that are likely to get you hit? Just a head's up."

"No, they were usually too busy trying to hit me," came the smooth reply. Startled, John turned to stare at the other boy. While Sherlock continued shelving, unfazed, there seemed to be some tightness in his frame, a tense lift to his lips that belied mirth as much as anxiety.

"Well then, I can't imagine they connected all that often, git."

If John's unusual familiarity perturbed Sherlock, it didn't show.

"No, not at all," he said, barely masking the edge of a smirk.

...

"I can't believe you still got detention! I mean, you were standing up for those first years. McGonagall should have given you points for going up against a Slytherin."

In spite of the librarian's best glares, Molly's normally soft voice carried down the stacks as she trotted next to John. Having returned early from a Potions Club meeting and found John bracing himself for his third night of detention, Molly had determined to escort him in a sweet show of solidarity. Of course, it meant some on-the-spot innovation on John's part when she asked just why he had a week of detention.

"Trust me, she wanted to. But you know McGonagall and her rules." John stopped a few shelves from where he'd been assigned.

"But don't worry about it Molls. Thanks for suffering through my walk of shame."

John had only been teasing about said shame until the very moment that Sherlock Holmes deigned to stick his fat head out between the stacks.

"Oh, ah, hullo Sherlock," Molly said, a blush rising on her cheeks. "I didn't know you were here too."

"Good evening, Molly,” Sherlock purred, chiming in just as John' s flat voice managed, "Oh, yeah, he helped too."

It took a moment for Sherlock's voice to register; while not quite predatory, the dark tone behind Sherlock's greeting to Molly was almost dangerously delicious. John physically attempted to shake the traitorous thought from him mind.

"Sorry I couldn't make it to the potion's meeting," the dark haired boy continued, "But you'll keep me updated on the progress of the artificial mandrake, yes?"

John's jaw dropped at how utterly sinful Sherlock's voice could be. Molly squeaked out something in the affirmative and fled the library with barely a good night. While John had seen Molly uncomfortable and shy before, he'd never seen the girl beat such a speedy and red-faced retreat.

John pushed past Sherlock to get between the stacks and to the parchment containing the evening's assignment... and if the heat that seemed to radiate off of Sherlock's impossibly slender frame made John's heart suddenly thrill, well, the boy was still a complete arse.

"You didn't have to do that to poor Molly," John groused. "She's shy enough as is."

"And you didn't have make yourself into an epic hero simply to justify a detention."

Sherlock shouldered John aside and snatched back the book list. Pale eyes flicked from line to line then rolled to the heavens. "Another stack of Lupwigs and their medicinal properties," he sighed, dark and sensual act dropped for something decidedly more obnoxious.

Having determined the same, John's arms were already book-laden by the time Sherlock stopped muttering to himself and set down the list.

"I considered going for the martyr angle," John continued, conversationally, "but I thought the idea of me suffering because you randomly decided to spell me nude in a hallway wouldn't have done Molly any good."

"You were not nude," Sherlock protested. The tower of books in his arms was impressively large given the thinness of his frame; John could see the slight line of well-defined muscles beneath the white of Sherlock's shirt. John ignored it very, very well.

"I don't really think the extent of my undress would have really mattered much to her. You know she's head-over-heels for you, yeah?"

For a handful of minutes, the only sound between them was the heavy rush of breath and the slide of books. Not until the silence rose did John notice Sherlock's irregular chattiness; only now that it was gone did John think to miss it.

"Molly is not particularly my type," Sherlock said. The sigh behind his voice seemed to waver between annoyance and something John would never have accused Sherlock of before: hesitance. Resisting the strong desire to turn and scan Sherlock's face, John kept shelving.

"I consider my Work to take precedence over any such sordid teenage intrigue," Sherlock said. At this point, John did turn to face the other boy, though Sherlock looked resolutely forward. It was a look John had seen before, the look of a person so used to being harassed for being different that the only option was to shut down, close off.

For a fraction of a second, Sherlock so reminded John of Harry that his heart ached. John nearly reached for the pale wrist, the frantic bird flutter of pulse beneath it. He stopped himself. Even framed in the warm gold of the library's lanterns Sherlock seemed so cold, ice and curling iron wrought into some statue of man.

"Me too," John finally said.

"Don't be nonsensical, Watson. You don't even know what the Work is."

"Not that part," John said, smiling despite himself. Sherlock gaped, snapped his mouth shut with a click of teeth, and huffed quietly for the rest of the hour.

...

"Professor Moriarty is clearly gay," Sherlock said by way of greeting.

"And hello to you too."

For the first time, John had beaten Sherlock to detention; given how strange that was, John was hardly surprised to see that Sherlock had been up to something stranger.

"Haven't you been paying attention?" Sherlock sighed, pulling his fingers through his locks in what was clearly a gesture of frustration. His wand was sticking out of his back pocket, and his shirt looked like it had been neither washed nor pressed in days. Trousers, too short at the ankles after an apparent growth spurt, only heightened Sherlock's look of absent mindedness.

"Ah, no, I haven't. You just got here. Before this, I was at dinner and you were apparently off in the  
dungeons, spying on professors or something equally stupid." As hard as he tried, John couldn't help but laugh halfway through his response. Sherlock looked a mess.

With a snort, Sherlock stepped forward. "It's not my fault that you weren't around to listen." He leaned past John to glance at the mounting number of books to be arranged.

"And it's not my fault that you've decided to talk to me when you're alone."

Their eyes met, gazes seemed to push and then break as both boys broke into laughter, realizing how childish they sounded. The warmth that filled John's stomach at the low rumble of Sherlock's laughter made him feel giddy, as if strange bubbles were rising from the pit of him up, filling all of the uncertain spaces.

"Well, since you've decided you're speaking to me, go ahead and tell me what makes you think Moriarty's, well, you know."

"I don't think, I know. Do try to keep up."

Sherlock picked a thick tome from the pile. He stepped into John's space and dropped the book into his hands. And though the graceful power of Sherlock's fingers were tempting, John did not break eye contact.  
...

"You can tell by the photos he hangs in his office that Professor Longbottom will be leaving his wife soon-likely by the end of term. They're all pictures of the new Order and "Dumbledore's Army". He's too caught up in the thrill of the past to stay with someone so boring."

Sherlock's rapid observations - deductions, he'd called them the night before - flowed out between a smug smile, unimpeded by his current filing task.

"There's no way you can tell that," John said with a snort. He leaned against the bookshelf opposite to where Sherlock was working, his own shelving done until the next pile of books appeared. "It's one thing to figure out all that about a person in the present, but there's no way you can know what's going to happen in the future. Unless you have the Sight and have been holding out on me." John waggled his eyebrows as Sherlock let out a disgusted sigh.

"Nonsensical tripe. I'm offended you'd compare my skills to that chicanery my brother utilizes." Sherlock paused, pale eyes sweeping across John's amused face. "If there's no way I could deduce something that will happen in the future, then how could I possibly know that you're going to be volunteering at St. Mungo's next summer despite your constant talk of training as an Auror? Or that your sister will be bringing home her Muggle girlfriend over the winter holidays? Or-"

"Alright, fine fine fine! That's enough." John threw up his hands, hoping to stop Sherlock's speech  
before it undoubtedly became more personal. "I suppose I should be flattered you noticed. You say that kind of stuff to most people and they'd freak, you know? They'd accuse you of being a stalker."

"Well then, I suppose it's ideal that you're not most people."

Sherlock held John's gaze as he said it; the intensity of Sherlock's stare was too great. There was no deception in his words, no guile or hidden humor at John's expense. John looked away.

A jumbled heat started right under his ribs and sank down his spine. The feeling gripped his gut. Certainly, John had been taken aback by the Ravenclaw before, made to feel surprised, or angry, or even breathless, but never had he felt so... anxious.

He forced himself to meet Sherlock's eyes again, and found himself looking sharply up. John's pulse crescendoed in his ears; Sherlock had stepped close and leaned in, too near to be construed as just friendly. His thoughts scattered: Was this really...? Maybe Sherlock didn't understand personal space? Was he about to attack? Could Sherlock read minds? Had John rightly understood the pants?

Sherlock tipped his head forward and John let out a hiss of breath. Dark pupils wreathed in silver took him in, unblinking. For a split second, John considered-

"Let me try," John breathed. Sherlock's lips parted, teeth coming down to bite lightly on his plush bottom lip.

"Let me try to figure it out. You give me a deduction, and I'll try to tell you how you got it."

Sherlock pulled back, eyes closing in a flutter of long lashes. One slender hand pulled through his curls, a gesture John had learned meant irritation.

Sherlock's compliment, his closeness, had sent John into an ungainly mental tumble. Irritation, though, he could handle for now.

"Alright Watson, let's see how atrocious your deductive skills are." The other boy's eyes flicked open, more light blue than silver at a distance. His hands shifted from head to hips, slipping into his back pockets in an obvious show of defiance.

"Hey, have some faith!"

"If these last few days have been any indication of your powers of observation, I shudder to imagine how it is you manage to make it to class fully dressed every day. Though there was that one time..."

Though Sherlock's words were cutting, the Cheshire grin he sent John's way raised more indignation than ire.

"Okay, I get it, you're brilliant and an arse, just let me try."

One eye roll later, Sherlock spit out his first deduction for John.

"Sebastian Wilkes is stealing honey trumpet root from Greenhouse Two to lace a variety of Weasley brand confections with the powerful hallucinogen."

John's jaw dropped. "He what? But he's a prefect!"

"He could be a blasted-end skrewt for all I care. How did I figure it out?"

Pushing off from the bookshelf, John began to pace, circling Sherlock as he thought. The other teen watched him with narrowed eyes, waiting for John's answer. Without looking, John could feel the power of those eyes on him. Pace and pulse quickened.

"Well, Wilkes has been having a lot of trouble with the first years..."

And with that, John and Sherlock began, their conversation a mix of mystery and banter. John guessed at and Sherlock revealed the sordid lives of their classmates. Each leap of Sherlock's logic seemed strangely surreal, yet as he corrected John's misperceptions and explained his own connections, John became ever more a believer. The only thing more fantastic (in every sense of the word) than Sherlock's deductions was the sharp look he sent John when John came to the right conclusion, his own observation spot on. A mix of pride and heat, Sherlock's stare sent John sputtering on more than one occasion.  
"Molly plans on taking me to Hogsmeade next weekend, as a date," Sherlock said. Each new deduction rolled out faster than John could untangle them; he'd just tripped through a particularly snarly series involving Sally Donovan and some reedy looking Slytherin when Sherlock spat out the next.

"I can see your special investigator skills were hard pressed with that one," John said. "She's mad about you."

"Obviously. But how do I know it will be this weekend and not the next? Or a year from now? Our Molly is hardly a Gryffindor."

Sherlock's tone may have been petulant (put off, no doubt, by John's lack of amazement at his deductive reasoning), but the way his voice rounded around "our" sent a ripple of heat across his skin. The cold-hot flush of feeling (*adrenaline*, John’s Muggle mum had once explained) made him want to squirm, to loose a soft gasp—instead, John ran his tongue over his lips, a habit borne of nerves and a need for restraint.

“Well… you and Molly are in the Potion’s Club together…”, John began, “Molly is thinking about being a Healer and so she’s getting extra work in on her Potions work, but you… you’re in it because of the variety. You can do so much with potions, so many crazy ingredients, you’d never get bored with it.” Sherlock’s eyes (previously, _startlingly_ honed in on his lips) flicked up to John’s. John picked up speed, suddenly sure of himself. “Molly has this uncle - runs an apothecary in Diagon Alley - and she’s been talking about how he’ll be in Hogsmeade for the next two weeks setting up a new shop. Our next Hogesmeade weekend is upcoming and, knowing that you love Potions so much, Molly figured you must have an interest, and so she’s going to invite you. To meet him. On a date.”

Too wrapped up in his deduction, John didn’t notice how the stack of books on the cart disappeared with a soft susurrus; instead, it was Sherlock’s sudden step away that drew attention to the end of their detention. The lean boy was already to the end of the row by the time John stuttered back to speech.

“So, did I get it right?”

Sherlock wheeled around the end of the shelves, out of sight even as his voice drifted back to John: “Not even close - Molly approached me yesterday after dinner to ask.”

A strange tightness gripped his chest and grasped at his gut, the thought that Molly had actually- that Sherlock would? John shook his head and forced out a chuckle.

“You’re absolutely insufferable, you know?”

A heartbeat later Sherlock pulled himself back around the stack, letting his fingers drum across the wood as his lips twitched into an obtrusively smug grin. For just a breath John allowed himself to  
admire how the boy’s lips met in plump rounds, how the rise in his cheeks made his cheekbones even more precipitous.

“Just one of my many charms, Watson.”

And with a wink, he was gone.

…

He slunk in just past one, moving so quietly that John didn’t notice his arrival until the bed shifted under the weight of hand and knee. John’s eyes drifted open lazily. Barely visible in the dim light that filtered through a crack in his bed hangings, Sherlock was more form than face, the dark suggestion of a predator rather than the gnashing of teeth and claw.

“Deduced the way in, did you?” John murmured. His limbs still felt limp from sleep, though he became aware of the sudden pick up in his pulse.

The chuckle that met his ears came laced with a growl. “A few rhythmic thumps are hardly a challenge.”

John’s bed creaked slightly as Sherlock brought the rest of him up onto it. Feeling a hand on each side of his head and a knee on either side of his thighs, John’s heartbeat became more than just a few rhythmic thumps.

“Are you calling me _boring_?”

Despite the poor lighting John could see an impression of that fluid grin, a grin that hinted at bright, focused eyes. Sherlock’s head ducked down, down to John’s skin, nose settling just below John’s ear. The very motion made John’s stomach twist expectantly; warmth flooded his skin as Sherlock’s breath became words.

“Don’t take it personally. Not everything is about you, John.”

The slight gasp released under the pressure of Sherlock’s voice was one John couldn’t hope to deter. His toes curled as his body tensed and lifted ever so slightly to graze the one above. John turned his head slightly. Using nose and cheek alone he nuzzled Sherlock’s face back up to his. The heat of Sherlock’s eyes, made near-black by pupil and night, was matched only by their intensity as the boy stared at John.

“Liar.”

Sherlock let out a whoosh of breath that was half-laugh, half-pant. Settling back on his knees, he moved his hands from the bed to John’s face, from John’s face down to his collarbones, past chest and over nipples (where they paused, just for a moment, to test slender fingers along each bump), and  
finally across the stretch of tanned stomach to halt at the elastic line of John’s pants. A flush followed Sherlock’s fingers during their journey. Sputtering gasps filled John’s ears—his or Sherlock’s, he couldn’t tell. A glance back up to John. A shadowed smirk. Three fingers slipped below the fabric, and the groan the motion elicited was loud enough to startle John from his own dream.

…

Eyes wide in the dark, John stared at the empty space above him. He was alone and painfully aware of the erection that pressed up between his clenched thighs.

Fisting his cock through his pants, a thought suddenly struck him.

“ _Oh_ ,” he hissed as he came.

…

The first hour of Wednesday detention with Sherlock was a study in willpower. Despite their near-friendly banter the night before, the Ravenclaw boy acted aloof when John arrived, sparing no more than two sentences to command John to begin on the designated shelf. Sherlock wordlessly started on the shelves next to John, re-shelving books in what looked like a semblance of the order they’d been given by the librarian. Careful not to look at Sherlock (or the way his pale digits slipped down the spine of every book he placed), John managed to focus on his task for nearly thirty minutes.

As he fell into the mechanical rhythm of stacking and shelving, though, John’s thoughts began to drift back to his dream and the boy at his side. Sherlock was on average manic, to be sure, mood soaring up and then plummeting down like an unwieldy _Wingardium Leviosa_. Perhaps John had misinterpreted his fickle interest for something more, had met the hard force of his stare and assumed he piqued more interest in Sherlock than a simple deductive experiment. But then he remembered how he got this detention in the first place. There was no mistaking the purpose of Sherlock’s spell (though the intent behind it proved somewhat opaque). There was no erasing the blue of Sherlock’s irises, thinned to a pale line by gaping pupils. And most of all, there was no way of masking the look that Sherlock was sending him now, a look caught out of the corner of John’s eye in a space Sherlock must have thought he wasn’t looking. John may not have been Sherlock, but he wasn’t an idiot (at least, not anymore).

With a resolute thud the last book in John’s stack settled on the shelf. Stretching his arms above his head, John turned to face Sherlock and noted with some pleasure how Sherlock’s sideways glance started at John’s abdomen and worked up. John sighed and leisurely leaned against the built-in desk that jutted out, hip height, from one of the shelves. If John slid ever so slightly closer to Sherlock in the process, if he suddenly found himself nearly a few inches from his knee brushing Sherlock’s thigh, well, then, Sherlock seemed too focused on his work to noticeably react. Humming a short note to clear his throat (and ensure that his voice would still work), John tilted his up to gaze at the other boy.

“Sherlock?”

“Mmm?” He did not even glance down, simply continued to shelve.

“You never did manage to charm the _pants_ off of me.”

Were it not for the regular whir and thud of books appearing to be shelved, John would have thought the entire library had been charmed to stillness. Sherlock stood frozen, brow furrowed and lips parted slightly. A slender gilded volume on nifflers hovered inches from the shelf, still held in Sherlock’s paralyzed grip. After a long moment, he set the book down in a slow, controlled motion. In profile Sherlock was electrifying; with a shiver, John realised he looked angry. 

“You are…”

Low but clear, his voice seemed as sharp as his pale face.

“I am?” John leaned further back on the desk, back nearly touching the shelf. 

"The most obtuse..."

And Sherlock was before him, leaning close, bracing his arms on either side of John's body. He felt Sherlock's knees press against his.

"Most painfully..."

Sturdy hands reached up and pulled at Sherlock's frenzy of dark curls. John tugged him down, held Sherlock's face just millimeters from his. 

"You should have just said something, you prat.”

They moved together, a synchronous smash of lips and teeth and tongue and need.

…

“Sherlock. Just take. Them. _Off_.”

Separated by one cotton layer, the heat from Sherlock’s hand and the ache in John’s groin were still too distant. John canted his hips harder into Sherlock’s touch, rubbing cock and cloth in supplication. Teeth parted with the fleshy lobe of John’s ear as he begged; Sherlock leaned back and scrabbled on the table behind him for his wand.

“No,” Sherlock hissed. He ground his hips into John’s, pushing him back against the bookshelf. Wand firmly in hand, Sherlock muttered a summoning spell. Where there had been bare chest there was now a collared shirt and yellow-and-black tie; John’s bare legs were suddenly covered by his thick trousers. The groan that spilled from John’s mouth was one of frustration rather than lust—they had been at this for the last forty minutes. John pulled Sherlock tight against him and planted his hands firmly at Sherlock’s waist. Without stopping for permission, he tugged at the bottom of Sherlock’s dress shirt, pulling it violently from his trousers and up to nearly his navel.

“You see? There are some things that can just be done with the hands. No spells necessary!”

Sherlock grunted as John slid his hands up Sherlock’s back and abruptly dragged his nails back down. He met John’s lips with a bruising kiss before pulling away slightly.

“That’s _not_ the point John, and you know it,” he grit out. He quivered at the sting of John’s desperate clawing, but did not pause as he raised his wand and again leveled an incantation. Sherlock’s hushed spell became John’s yelped curse. A rush of cool air raised goose bumps along his arms and legs; Sherlock quickly smoothed a hot hand over John’s bare thighs before reaching his ever-present pants and moaning.

“Still don’t quite have the right words, huh?” John said. Long fingers cupped his erection through the teasing cloth. “How long have you been working on this spell now, t-two weeks?” Vindictive, Sherlock gave John a squeezing stroke that sent him into momentary speechlessness.

“I didn’t have the proper _test equipment_ before,” Sherlock growled. He stroked John once more  
through his pants, and in the next instant John was clothed.

As soon as he realised he was fully dressed once more, John shifted his hands from back to front and shoved Sherlock away from him. The other boy sputtered, taken aback. John smirked, leaning back against the bookshelf.

“Test equipment is good and all,” John said, one hand moving lazily down to his groin, “Real good, in fact. But you know, I think all of this fieldwork is getting you _distracted_.” His other hand worked its way to his collar and began loosening his tie and fumbling with buttons. “Go ahead. Keep dressing and undressing me.” John slipped his hand under the open shirt and pinched at his own nipple. He fixed his eyes on Sherlock as he stroked his erection through tented trousers. “From where you are, you should have plenty of opportunities for… ah…intense _observation_.”

There was a moan. One moment, there were two layers between hand and prick, and in the next there was only one. John pressed down more firmly, allowing himself a gasp. Sherlock’s frustration at failure came in the form of John being clothed just a second after that; as Sherlock charmed and uncharmed him, John basked in the flickering sensations of heat and cold, cover and exposure, thick cloth and thin friction. Each rush of bare flesh sent a deeper spurt of arousal straight down his gut, each moment that he found himself once again near-nude re-sparking the sensation. Each time, Sherlock managed to only strip him down to his pants.

Unconsciously, Sherlock stepped forward. John could see the sharp outline of Sherlock’s cock as it strained and twitched in his trousers. With an explanation that could only ever make sense to Sherlock, the boy had justified just the night before why he would not allow John to disrobe him yet, despite the fact that John was not the arse insisting on waiting until he came up with a spell to do it. And so as Sherlock stepped forward, John slipped a hand under the elastic of his pants and allowed his thumb to roll slowly over the head of his prick. He did not pull it out, just kept fingers and erection covered as he caressed himself. The rampant dressing and undressing stalled. He looked up to see Sherlock wholly riveted on the raised circle John’s thumb made under the underwear. Sherlock again came closer.

“No you don’t,” John muttered. “ _Observation_ , remember?” 

As if John’s words had snapped him out of a trance, Sherlock became a flurry of motion. Fingers found their way to dark curls, curls that frizzed and stuck up strangely as sweat from Sherlock’s forehead and palms mingled with them. For having remained untouched he looked hopelessly debauched: hair mussed, neck and cheeks flushed, lips parted ever-so-slightly as he panted heavily at the sight of John’s ministrations.

“Two whole days of this, John,” Sherlock groaned. The way Sherlock drew out the syllables of his name nearly made John come, then and there, still in his pants. Drawing a shaky breath, John pulled his hands away from his own erection.

“And whose fault is that? ‘ _No John, it has to be my spell’_ ,” he teased, “‘ _It’s the principle_.’”

Sherlock grimaced. In the midst of all of the tension, the sheer frustration of it all, John marveled at how such an ugly look could be so arousing. He resisted the urge to drag the other boy close and be done with it. 

“Well, get on with it!”

Sherlock took no further prompting. John bit back a sigh as his clothes were summoned back over his skin, knowing they’d be gone again soon enough - and hopefully, this time, it would be all of them. It was their last night of detention, and while John hoped (Merlin, hoped) that the end of their forced time together wouldn’t be the end of their time, it was obvious there was a heightened urgency in Sherlock’s spellcasting. Both of them, under some kind of deadline-driven spell, unwilling to give in. 

And as much as John wanted this, wanted to feel Sherlock against his skin, he couldn’t deny the thrill of the other boy’s mad plot, the way it made his pulse leap into his throat. Cool air pressed against him once more - naked, except for his pants. John met Sherlock’s desperate gaze. They both shivered. John’s clothes reappeared.

“Just think, Sherlock,” John breathed. “Use that massive, bloody obnoxious brain of yours and just do it.”

He stilled, eyes meeting John’s once more. For a few moments Sherlock simply stared. His entire frame seemed to lift and shudder with each heavy breath. Sherlock was the split-second before a spell hit, that moment of shock and utter amazement and fear and a fury of silver sparks: stretched into slow motion yet inescapable. John felt petrified. Sherlock’s lips moved but the roar in John’s ears drowned it out. Suddenly, everything was two bruised lips and the crackle of magic over every inch of skin.

John let out a heavy breath. He could still feel the spell, flushing and tingling over his completely nude form. 

“John…”

A flush blazed up John’s chest and neck, and for every second that John had wanted it, he abruptly found he couldn’t look up at Sherlock. The Ravenclaw was so sharp, so logical, and what if John wasn’t what he had deduced, wasn’t what Sherlock wanted now that he was laid out before him. Feeling pinned between boy and bookshelf, John couldn’t help but glance to the end of the row. What if the aversion spell they’d set up for unwanted eyes had failed? What if they got caught? What if Sherlock, ever fickle, would be done now that he’d gotten what he wanted?

“John.”

Sherlock pressed close. Despite himself, John’s cock twitched, his body still very interested and very exposed. John squirmed. Long fingers pressed lightly on each thigh. He inhaled sharply. Looked up. Couldn’t read that expression if he tried.

“Well, looks like you d-”

John was cut off by those lips, warm and soft, and a hard line of teeth. The space between them disappeared as Sherlock dragged John forward until their erections met. For a few seconds, all either could do was move - rut and grind and press until just being close wasn't enough. With a groan, John shifted back to get at Sherlock's trousers, and had nearly undone the button when Sherlock put a hand over his to stop him. 

"What now?" John snapped. He glanced away once more, feeling too exposed, too defensive for Sherlock to suddenly be stopping. The other boy was silent. John's pulse was still raging in his ears, but after a few heartbeats John started to hear his own voice, that conscience niggling in the back of his head whispering that maybe, maybe Sherlock was the one who was feeling uncertain, vulnerable. After all, he was the one who'd tried to use a spell to catch John's attention, rather than just coming up and talking to him. And maybe, even though John was the one who was very naked, and very obviously erect and open and in no place to really defend himself or his dignity, Sherlock was the one who needed reassurance.

"Look, Sherlock, if this isn't the right-"

Sherlock dropped to his knees, wedging himself between John's legs. He placed one hand on John's thigh and the other right at his hip, bracing himself as he leaned in. Slowly, almost reverently, Sherlock placed his parted lips on the head of John's cock.

Even at such a light touch John shuddered and moaned. Sherlock looked up at him intently, and John nodded, gasped something that in another world might have sounded like "Oh Merlin, please."

He felt Sherlock's tongue sweep along his head. Just as John was adjusting to the sensation, feverishly telling himself that he would not come then and there, Sherlock's lips slid down his shaft, taking the whole of his length in his mouth. He moved slowly at first, head rising and falling, tongue sliding, licking, the occasional scrape of teeth just on the side of too hard - uncertain, but gaining confidence, gaining momentum with each moan he pulled from John, with each curse John bit out.

"Sherlock, I'm gonna- I'm-"

Rather than pull away, Sherlock sunk further down, hollowing his cheeks as he sucked hard. 

John came in a string of moans and half-worded adorations, in a rush of heat that flared across his skin and left him shuddering, panting, wiped of all thoughts. When he finally re-entered reality, he felt the light flick of Sherlock's tongue along his cock, pleasant to the point of pain. John placed his hands on Sherlock's shoulders, under his arms, and fumblingly hauled him up to head height.

The boy's eyes were wide, almost glassy, and his hair stuck up at odd angles, shaped by sweat. He looked undone, and needy, and more wonderful than anything John had ever seen - John pulled him closer and pressed their lips together. Kissing slowly, John swept his tongue between Sherlock's lips. The taste of salt, a tinge of something acidic; John marveled at the strangeness of tasting himself on Sherlock.

Sherlock finally pulled away, just enough to look John in the eye, not enough to break contact. 

"Was that-?" he asked, and the genuine concern, the anxious need to please that Sherlock hid so well, struck John to the core of his still pouring heart.

"You were brilliant, Sherlock, just amazing," John breathed. "I'd like to - if you'd like-"

Sherlock nodded eagerly, and the moment of soft sweetness ended when he pressed close and ground his still-throbbing erection into John's thigh. 

"Hold on a sec," John muttered. He reached out for his wand, which had been abandoned further down the bookshelf what felt like aeons ago. 

"John?"

John gripped his wand, gave it a circle and a flick in Sherlock's direction, and murmured something under his breath. The buttons on Sherlock's shirt and trousers began to pop open simultaneously, clothes peeling away from him on their own. Sherlock's pants gently tore down the seams, fell away, then got busy restitching themselves on the floor. 

Sherlock looked down to himself, gloriously nude and brilliantly erect, then looked to John.

"This whole time..." He started.

"I tried to tell you!" John said, snickering.

"You just sat there..." Sherlock pulled a hand through his hair.

"You insisted on doing it yourself."

"When we could have been..." Sherlock looked scandalized, but hardly as mad as he likely had a right to be. Even with his admonishments, he was drawing closer, moving to fit his body against John's.

"Admit it, Sherlock, you loved the challenge."

"And you think I'm the arrogant arse," Sherlock muttered. 

John began to respond, but was cut off by a very needy, very insistent pair of lips.

**Author's Note:**

> Keep an eye out for the final chapter, which should hopefully be up this week. 
> 
> Summary: John has a week of detention with Sherlock who, despite his best efforts, decidedly did not charm his *pants* off.
> 
> Be forewarned, it's pretty much going to be a pwp. Cheers!


End file.
